1. Field of the Invention
The present invention relates to a camera having an operation member on a rear cover thereof, a camera whose picture size is variable and a picture size switching mechanism, and a click stop mechanism.
2. Description of the Prior Art
In a known variable picture size camera in which the picture size can be switched between, for example, a standard picture size and a panoramic picture size (laterally elongated picture plane), an operation member which is adapted to turn the power source ON or OFF and an operation member which is adapted to switch the picture size are separately provided. Namely, the two operation members are independently actuated. Moreover, in a known camera having additional operation members for actuating an electrical signal generation device and a mechanical operation device, incorporated in the camera body, the operation members are separately or individually provided. Generally speaking, a simplification of the operation system has been needed to facilitate the assembly and reduce the manufacturing cost. However, for example, in a water proof camera, the separate water tight structures of the operation members for the electrical signal generation device (e.g., power switching mechanism) and for the mechanical operation device (e.g., picture size switching mechanism) makes the assembly complicate and expensive.
In the case that the operation members are provided on the rear cover of the camera, so that the electrical signal generation device or the mechanical operation device, incorporated in the camera body can be actuated from the outside of the camera body by the operation members, it is difficult to establish an interconnection between the external operation members and the internal electrical signal generation device or the mechanical operation device, etc. When the rear cover is opened, the operation members are disconnected from the corresponding internal device to be actuated. Consequently, if the operation member is actuated when the rear cover is open, there is a possibility that a positional relationship or association therebetween is broken or fails, or the rear cover cannot be closed.
One solution to prevent an appropriate association between the operation member and the internal operation mechanism to be actuated by the operation member from being broken when the rear cover is open is to bias the operation member and the internal operation mechanism toward the association or engagement position. However, in this solution, it is impossible to forcibly close the rear cover while the operation member is maintained in a position different from the engagement position. To make it possible to forcibly close the rear cover, in a conventional camera in which the internal operation mechanism of the camera is, for example, the picture size switching mechanism, a light interception frame which is adapted to vary the picture size is elastically deformed when the forced operation is carried out. However, it is not advisable to deform the light interception frame, from the viewpoint of duration and reliability of the operation thereof.
Furthermore, in a variable picture size camera, a pair of light interception frames for a panoramic picture size are provided in the vicinity of an aperture which defines a standard picture plane, so that the light interception frames can be moved in opposite directions to cover upper and lower edges of the standard picture plane to thereby vary the picture size. The light interception frames must be reliably moved between a standard picture size position in which the standard picture size is obtained and a panoramic picture size position in which a panoramic picture size is obtained, and must be firmly held in the standard picture size position or the panoramic picture size position. To this end, in conventional cameras, a reversible action biasing spring whose direction of action is reversed at a specific spring position is used to move and hold the light interception frames to and in the two extremity positions, or a unidirectional biasing spring is used to continuously bias the light interception frames toward one of the two extremity positions, so that when an external force in a direction opposite to the biasing direction is released, the light interception frames are automatically returned to the one extremity position. However, the biasing spring complicates the structure of the camera.
Moreover, in a operation mechanism, not limited to the camera, a click stop mechanism which includes a click spring and a click projection which can be disengageably engaged by the click spring is often employed to stably hold the operation member which is biased in one direction in one of specific positions so as to move the operation member from the specific position when a predetermined strength of force is applied. In a conventional click stop mechanism, the engagement of the click spring and the click projection at each specific position (engagement position) takes place only at one point thereof, thus resulting in an unstable engagement. In addition to the foregoing, in a conventional click stop mechanism, the position of engagement between the click spring and the click projection is different depending on the direction of the movement of the operation member or the engagement positions (click positions), so that an operator would sense a different amount of operation resistance.
It is an object of the present invention to provide a small, inexpensive and high operation efficiency camera in which an electrical signal generation device and a mechanical operation device are incorporated in a camera body and operation members are provided on a rear cover of the camera body, wherein an operation portion is simplified.
A second object of the present invention is to provide a small and inexpensive variable picture size camera in which the assembly can be simplified by simplifying an operation portion thereof.
A third object of the present invention is to provide a simple and inexpensive picture size switching mechanism for a variable picture size camera in which light interception frames can be reliably held at extremity positions without providing a biasing member to return the light interception frames.
A fourth object of the present invention is to make it possible to carry out a forced operation of the operation device upon closing the rear cover which has been opened (in a camera having an operation mechanism such as a picture size switching mechanism and an operation device for the same provided in a camera body and a rear cover, respectively) without burdening the operation mechanism in the camera body (e.g., picture size switching mechanism).
A fifth object of the present invention is to provide a simple click stop mechanism in which an operation member can be stably held in a specific position and an operator""s sense of operation hardly changes regardless of the operation direction or operation position.
To achieve the first object of the present invention, there is provided a camera having a rear cover with an operation member thereon, including an electrical signal generation device and a mechanical operation device, provided in a camera body; a movable common operation member provided on the rear cover to actuate the electrical signal generation device and the mechanical operation device; a movable association member in the camera body, which is moved in accordance with the movement of the common operation member when the rear cover is closed, to actuate both the electrical signal generation device and the mechanical operation device; a biasing member on the rear cover, for holding the common operation member at a predetermined position when the rear cover is opened, regardless of the position of the common operation member when the rear cover has been closed; and a biasing member on the camera body, for holding the association member at a predetermined position when the rear cover is opened, regardless of the position of the association member when the rear cover has been closed.
With this arrangement, since the operation member can be commonly used, not only can the manufacturing cost be reduced but also assembly can be simplified. Moreover, since there is no phase difference between the common operation member and the member to be associated therewith when the rear cover (which has been opened) is closed, the camera is easy to handle.
Preferably, the common operation member includes a dial member which is rotatably supported by the rear cover and the association member includes a rotary plate which is supported by the camera body to rotate about the same axis as the axis of rotation of the dial member, so that the rotary plate is rotated in accordance with the rotation of the dial member when the rear cover is closed. The rotary plate can be provided with an electrical contact portion which constitutes the electrical signal generation device, and an operation cam which actuates the mechanical operation device in accordance with the angular position of the rotary plate.
For instance, the electrical signal generation device includes a power switch of the camera, and the mechanical operation device includes a picture size switching mechanism which varies the picture plane between a standard size picture plane and a laterally elongated panoramic size picture plane which is obtained by obstructing upper and lower edges of the standard size picture plane.
If the above idea is applied to a variable picture size camera, the camera would include a camera body; a rear cover which opens and closes the back of the camera body; a power switch mechanism provided in the camera body; a picture size switching mechanism provided in the camera body, which switches the picture size between a standard picture plane and a laterally elongated picture plane in which upper and lower edges of the standard picture plane are obstructed; a common operation member provided on the rear cover, which actuates the power switch mechanism and the picture size switching mechanism; and an association drive mechanism which associates the operation of the common operation member with the operations of the power switch mechanism and the picture size switching mechanism when the rear cover is closed.
Consequently, the second object of the invention, i.e., the simplification of the operation system of the variable picture size camera can be achieved.
In the variable picture size camera, preferably, the common operation member includes a dial member which is rotatably supported by the rear cover, and the association drive mechanism includes a rotary plate which is supported by the camera body to rotate about the same axis as the axis of rotation of the common operation member, so that the rotary plate is rotated to carry out the ON/OFF operation of the power switch mechanism and the switching operation of the picture size switching mechanism between the standard picture plane and the laterally elongated picture plane; and a rotation transmission mechanism for transmitting the rotation of the common operation member to the rotary plate when the rear cover is closed.
In an embodiment, the common operation member includes three engagement positions when the rear cover is closed, and the rotary plate includes three angular positions corresponding to the three engagement positions of the common operation member and consisting of a first position in which the power switch is turned OFF and second and third positions in which the power switch is turned ON, so that the standard picture plane is held at the power-OFF position and one of the power-ON positions, and the laterally elongated picture plane is held at the other power-ON position. The common operation member and the rotary plate can be biased toward angular positions in which the operation states thereof correspond to each other and can be returned to respective biasing positions when the rear cover is opened. Preferably, the common operation member and the rotary plate are biased toward angular positions corresponding to the power-OFF position.
In an embodiment, the power switch mechanism includes a plurality of electrical contacts provided in the camera body, and electrical contact pieces which are provided on the rotary plate and are selectively brought into sliding contact with the electrical contacts in accordance with the angular position of the rotary plate.
Preferably, the picture size switching mechanism includes a stationary standard picture plane forming member provided in front of a film surface; a pair of light interception frames which are provided with light interception portions which can obstruct upper and lower edges of the standard picture plane and which are movable in the upward and downward direction of the standard picture plane to selectively define the standard picture plane or the laterally elongated picture plane; a light interception frame association mechanism which moves one of the light interception frames symmetrically with the other light interception frame with respect to the center of the picture plane when the other light interception frame is moved in the upward and downward direction; and a biasing spring which biases the light interception frames toward a position corresponding to the standard picture plane. The rotary plate can be provided with an operation cam which presses a follower pin provided on one of the light interception frames at a predetermined angular position to thereby move the light interception frames to a position corresponding to the laterally elongated picture plane.
The variable picture size camera can be provided with a finder optical system separate from a photographing optical system. The finder optical system can be provided therein with a field frame switching device which switches a finder field corresponding to the standard picture plane and a finder field corresponding to the laterally elongated picture plane in accordance with the operation of the common operation member.
Preferably, the field frame switching device mechanically moves a field frame forming member provided in the finder optical system, due to the moving force of the light interception frames. In an embodiment, the field frame switching device can be composed of a liquid crystal display whose transparent area can be selectively varied to define a field corresponding to the standard picture plane and a field corresponding to the laterally elongated picture plane, in accordance with the voltage supplied thereto, so that the electrical contact pieces provided on the rotary plate are in sliding contact with the electrical contact portion provided in the camera body to produce an electrical signal in accordance with the angular position of the rotary plate, whereby the voltage to be supplied to the liquid crystal display is controlled in accordance with the electrical signal to selectively form the field corresponding to the standard picture plane or the laterally elongated picture plane.
The camera having a rear cover with an operation member thereon and the variable picture size camera are preferably water-proof/drip-proof in which the common operation member and the rear cover are sealed in water-tight fashion.
The above mentioned basic idea of the present invention can be applied to a camera in which the common operation member, the power switch mechanism and the picture size switching mechanism are not separately provided on the rear cover and in the camera body. Namely, the operation system can be simplified since the common operation member can actuate both the power switch mechanism and the picture size switching mechanism.
To achieve the third object of the present invention, there is provided a picture size switching mechanism for a variable picture size camera in which a picture plane can be switched between an elongated standard picture plane and a laterally elongated picture plane in which upper and lower edges of the standard picture plane are obstructed, including a stationary standard picture plane forming member provided in front of a film surface; a pair of light interception frames which are provided with light interception portions which can obstruct upper and lower edges of the standard picture plane and which are movable in the upward and downward direction of the standard picture plane to selectively define the standard picture plane or the laterally elongated picture plane; a light interception frame association mechanism which moves one of the light interception frames symmetrically with the other light interception frame with respect to the center of the picture plane when the other light interception frame is moved in the upward and downward direction; a follower pin provided on one of the light interception frames; a rotatable cam member which is supported by the camera body to rotate about an axis substantially perpendicular to the picture plane; and first and second cam surfaces provided on the cam member, which are adapted to press the follower pin in accordance with the angular position of the rotatable cam member to thereby hold the light interception frames in positions corresponding to the standard picture plane and the laterally elongated picture plane, respectively.
With this arrangement, since the laterally elongated picture plane is obtained and held by the cam surfaces of the rotatable cam member, it is not necessary to provide a biasing member for the light interception frames, thus resulting in a simplification of the picture size switching mechanism.
In the picture size switching mechanism for a variable picture size camera, the first cam surface which is adapted to hold the light interception frames in the standard picture plane forming position includes an arched cam surface whose center is located on the axis of rotation of the rotatable cam member.
To achieve the fourth object of the present invention, there is provided a variable picture size camera including: a camera body; a rear cover which opens and closes the back of the camera body; a picture size switching mechanism provided in the camera body to switch a picture size; a picture size varying member which is supported on the surface of the camera body opposed to the rear cover and which is reciprocally moved in opposite directions to actuate the picture size switching mechanism; an operation member provided on the rear cover, which is selectively moved to a plurality of positions corresponding to the position and direction of the movement of the picture size varying member; a biasing member for biasing the picture size varying member and the operation member and holding the picture size varying member and the operation member in the respective engagement positions when the rear cover is open; and a retraction mechanism which deforms at least one of the picture size varying member and the operation member so that the rear cover which has been opened can be closed when the operation member is located in a position different from the engagement position established by the biasing member.
With this structure, if the forced operation such as the holding of the operation member at a position different from the biasing position upon the closure of the rear cover being attempted, the rear cover can be reliably closed due to the retraction mechanism.
The retraction mechanism can include an elastically deformable plate having a free end, which is provided on the picture size varying member and which is deformable in the direction substantially perpendicular to a plane defined by the movement of the picture size varying member; and an insertion projection provided on the operation member, which is inserted in the camera body when the rear cover is closed. The insertion projection can be engaged by the free end of the elastically deformable plate so as to transmit the movement of the operation member to the picture size varying member when the operation member is located in the engagement position by the biasing member upon closure of the rear cover, and the insertion projection is adapted to press and deform the elastically deformable plate in the direction substantially perpendicular to plane of the movement of the picture size varying member when the operation member is located in a position other than the engagement position upon closure of the rear cover.
Preferably, the elastically deformable plate is bent at the body portion of the picture size varying member so that the elastically deformable plate extends close to the rear cover toward the free end thereof. In this embodiment, the insertion projection of the operation member is provided with an arched surface portion which can contact with the elastically deformable plate to press and move the bent portion thereof.
In an embodiment, the picture size switching mechanism can switch the picture plane between the standard picture plane and the laterally elongated picture plane which is defined by an obstruction of upper and lower edges of the standard picture plane, and the biasing member biases the operation member and the picture size varying member toward respective standard picture plane forming positions. Consequently, upon closure of the rear cover which has been opened, the insertion projection is inserted in the camera body due to the presence of the bent portion without deforming the elastically deformable plate when the operation member is held in a laterally elongated picture plane forming position, and the insertion projection presses and deforms the bent portion of the elastically deformable plate when the operation member is returned from the laterally elongated picture plane forming position to the engagement position.
The camera body can be provided therein with a contact plate for an electric switch, and the elastically deformable plate is formed with electrical contact pieces integral therewith, which are in sliding contact with the contact plate in accordance with the movement of the picture size varying member. With this embodiment, the number of the elements can be reduced. Preferably, the operation member and the picture size varying member are supported on the rear cover and the camera body so as to rotate about the same axis.
If the picture size switching mechanism and the picture size varying member are replaced with another operation mechanism and a moving member on the camera body, in a camera having the retraction mechanism mentioned above, the invention can be applied to a camera other than the variable picture size camera, provided that the operation member is provided on the rear cover.
The present invention is also directed to a click stop mechanism comprising an operation member which is movable in opposite directions relative to a stationary member; a biasing member which biases the operation member in one direction; and a click spring and a click projection, one and the other of which are provided on the operation member or the stationary member respectively, to hold the operation member at a specific operation position against the biasing member.
According to the feature of the present invention, a pair of click projections are provided corresponding to the specific operation position, and the click spring is provided with a pair of stops corresponding to the pair of click projections. Consequently, in comparison with a conventional click stop mechanism in which the click spring and the click projection engage with each other at only one click position, a more stable engagement at the click positions can be obtained.
Preferably, the pair of click projections have sectional shapes which are line-symmetrical with respect to a median line perpendicular to the direction of the movement of the moving member; and wherein half of the cross sectional shape of each click projection is asymmetrical with the other half thereof with respect to a center line taken down the middle of the width thereof, the center line being parallel to the median line.
Consequently, an operator""s operation sense of resistance upon clicking is substantially the same in forward and return directions.
The pair of click projections can be each provided with a positioning surface substantially perpendicular to the direction of the movement of the moving member and an oblique surface inclined with respect thereto. The stops of the click spring can be each provided with an upright portion corresponding to the positioning surface, and an obliquely bent portion corresponding to the oblique surface. Preferably, the click spring is provided with a base plate portion extending substantially parallel with the direction of the movement of the operation member, and the upright portions and the obliquely bent portions are formed by bending the base plate portion at predetermined angles.
In an embodiment, a plurality of specific operation positions of the operation member are provided, and a pair of click projections and a pair of stops of the click spring are provided for each specific operation position to hold the operation member.
In an embodiment, the operation member includes a rotary member which rotates about an axis.
The operation member is preferably supported on a rear cover of a camera and the click projections are provided on the surface of a camera body that is opposed to the rear cover.
The present disclosure relates to subject matter contained in Japanese Patent Applications Nos. 10-28383, 10-28384, 10-28385 and 10-28386, all filed on Feb. 10, 1998, which are expressly incorporated herein in their entireties.